Adopt a libdrm man page

I just pushed some basic man page stuff to the libdrm repo, but won't have time to do any more pages for the next week or two.

But regardless, it would be cool if people could adopt some pages and push them out. The goal is to document every structure and function in the API header files, xf86drm.h and xf86drmMode.h, along with the chipset specific functions for each chipset under include/libdrm/.

I've based the man page template on stuff from X, but it may make sense to create our own man page section or put the functions in a different section, I'm definitely not attached to the current structure.

Thanks,